This invention is in the field of sewing machines; more particularly, the invention is concerned with a treadle drive for occasional use with a sewing machine which also is fitted with an electric motor.
The initial motor force for a sewing machine had to be supplied by an operator either by rotating a handwheel or, later, by the use of a foot treadle which freed the operator's hands for guiding a work material through the sewing machine. Early on, it was discovered that one of the problems with a foot treadle was that occasionally the sewing machine would begin rotating backwards which required an operator to rectify rotation, usually by corrective rotation of the handwheel. However, the most critical period in sewing machine operation is the initial operation which takes place before the position of the fabric plies has been fixed by stitches. Therefore, an operator required to take steps to correct sewing machine rotation must remove a hand from the task of fabric control in order to urge the handwheel in the correct rotation at the most critical time. In order to obviate this problem considerable inventive effort was devoted to schemes and devices which would prevent improper rotation of the sewing machine upon treadle actuation.
Subsequently, in some parts of the world, electric power became quite common and in these areas electric motors supplanted the use of foot treadles. However, in other areas of the world, electric power is only available during certain times and sewing machine operators must be provided with the option of utilizing the foot treadle or electrical motor. What is required is a sewing machine which may be operated by an electric motor or by a foot treadle and which will be deterred from reverse rotation while being actuated by the foot treadle.